[Techtalk] kppp 2.1.1 problem

[kansas_kennedy at phreaker.net]

IN RHL 7.3 while dialing with kppp 2.1.1 I got this following message and 
it disconnects and denies to connect to the net.

"Timeout expired while waiting for the PPP interface to come up"

In tail -f /var/log/messages shows:

pppd [2937] modprobe: can't locate module ppp0.

The modem is in ttyS0 port.

Can anyone help me to solve this problem?